<!DOCTYPE html>
<html lang="en">
<head>
	<meta charset="UTF-8">
	<title>Document</title>
	<style>
		*{padding: 0;margin: 0;}
		
		html,body{
			height: 100%;
		}
		
		/* 第二种布局 */
		.wrapper{
			position: relative;
			width: 100%;
			height: 100%;
		}
		.side-box{
			position: absolute;
			width: 200px;
			height: 100%;
			left: 0;
			top: 0;
		}
		.main-box{
			height: 100%;
			margin-left: 200px;
			background: #91dab9;
		}
		
	</style>
</head>
<body>
	<div class="wrapper">
		<div class="side-box">200px</div>
		<div class="main-box">自适应</div>
	</div>
</body>
</html>